:root {
    --primary-color: #d96b27;
    --primary-light: #fff5ed;
    --primary-soft: #fdecdb;
    --primary-dark: #b85417;
    --primary-border: #f5cca6;
    --text-color: #2d3748;
    --text-muted: #5a6a85;
    --heading-color: #1a202c;
    --bg-page: #fbf9f6;
    --bg-sidebar: #fff8f2;
    --bg-card: #ffffff;
    --border-color: #edd9c8;
    --code-bg: #282c34;
    --code-header-bg: #1e2227;
    --code-text: #abb2bf;
    --inline-code-bg: #f8ece2;
    --inline-code-text: #a84712;
    --table-header-bg: #faeadc;
    --table-border: #e8d5c4;
    --table-alt-row: #fffaf5;
    --blockquote-border: #e28743;
    --blockquote-bg: #fffbf7;
    --sidebar-width: 290px;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--text-color);
    background-color: var(--bg-page);
    line-height: 1.65;
    font-size: 15.5px;
}

.layout {
    display: flex;
    min-height: 100vh;
}

/* Sidebar Navigation */
.sidebar {
    width: var(--sidebar-width);
    min-width: var(--sidebar-width);
    background-color: var(--bg-sidebar);
    border-right: 1px solid var(--border-color);
    padding: 24px 16px;
    height: 100vh;
    position: sticky;
    top: 0;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
}

.sidebar-header {
    margin-bottom: 20px;
    padding-bottom: 14px;
    border-bottom: 1px solid var(--border-color);
}

.sidebar-title {
    font-size: 15px;
    font-weight: 700;
    color: var(--primary-dark);
    text-transform: uppercase;
    letter-spacing: 0.8px;
    margin: 0 0 4px 0;
}

.sidebar-subtitle {
    font-size: 12px;
    color: var(--text-muted);
    margin: 0;
}

.nav-menu {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 3px;
}

.nav-item a {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 12px;
    color: var(--text-color);
    text-decoration: none;
    border-radius: 6px;
    font-size: 13.5px;
    font-weight: 500;
    transition: all 0.15s ease-in-out;
    line-height: 1.35;
}

.nav-item a:hover {
    background-color: var(--primary-soft);
    color: var(--primary-dark);
}

.nav-item a.active {
    background-color: var(--primary-color);
    color: #ffffff;
    font-weight: 600;
    box-shadow: 0 2px 5px rgba(217, 107, 39, 0.25);
}

.nav-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 22px;
    height: 22px;
    padding: 0 5px;
    border-radius: 11px;
    background-color: var(--primary-border);
    color: var(--primary-dark);
    font-size: 11.5px;
    font-weight: 700;
    flex-shrink: 0;
}

.nav-item a.active .nav-badge {
    background-color: rgba(255, 255, 255, 0.25);
    color: #ffffff;
}

/* Main Content Area */
.content-wrapper {
    flex: 1;
    min-width: 0;
    max-width: 1080px;
    padding: 40px 48px 60px 48px;
    margin: 0 auto;
}

/* Headings */
h1 {
    font-size: 26px;
    color: var(--heading-color);
    margin: 0 0 24px 0;
    line-height: 1.35;
    font-weight: 700;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--primary-border);
}

h2 {
    font-size: 20px;
    color: var(--heading-color);
    margin: 36px 0 16px 0;
    line-height: 1.4;
    font-weight: 600;
}

h3 {
    font-size: 17px;
    color: var(--primary-dark);
    margin: 28px 0 12px 0;
    line-height: 1.4;
    font-weight: 600;
}

h4 {
    font-size: 15px;
    color: var(--heading-color);
    margin: 20px 0 10px 0;
    font-weight: 600;
}

p {
    margin: 0 0 16px 0;
}

ul, ol {
    margin: 0 0 18px 0;
    padding-left: 24px;
}

li {
    margin-bottom: 8px;
    line-height: 1.6;
}

hr {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: 32px 0;
}

/* Inline Code */
code {
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
    font-size: 13.5px;
    padding: 2px 5px;
    border-radius: 4px;
    background-color: var(--inline-code-bg);
    color: var(--inline-code-text);
    border: 1px solid #f2ded0;
}

/* Multi-line Code Block Demarcators */
.code-block-container {
    margin: 20px 0 24px 0;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 3px 8px rgba(0, 0, 0, 0.08);
    border: 1px solid #363b44;
}

.code-block-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: var(--code-header-bg);
    color: #e2e8f0;
    padding: 8px 14px;
    font-size: 12.5px;
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    font-weight: 600;
    border-bottom: 1px solid #2b3038;
}

.code-block-header .code-block-title {
    display: flex;
    align-items: center;
    gap: 10px;
}

.code-block-header .code-badge {
    display: inline-block;
    padding: 2px 7px;
    border-radius: 4px;
    font-size: 10.5px;
    font-weight: 700;
    letter-spacing: 0.6px;
    text-transform: uppercase;
}

.code-block-header .code-lang {
    color: #fab387;
    text-transform: uppercase;
    font-size: 11px;
    letter-spacing: 0.5px;
}

.code-block-header .code-filename {
    color: #cbd5e1;
}

.code-block-container pre {
    margin: 0;
    padding: 16px 18px;
    background-color: var(--code-bg);
    color: var(--code-text);
    overflow-x: auto;
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
    font-size: 13.5px;
    line-height: 1.55;
}

.code-block-container pre code {
    background: transparent;
    padding: 0;
    border: none;
    color: inherit;
    font-size: inherit;
}

/* Style 1: Enterprise Assistant Code (Diffs, App Config, App Implementations) */
.code-block-assistant {
    border-color: #2e5542;
    border-left: 4px solid #10b981;
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.12);
}

.code-block-assistant .code-block-header {
    background-color: #172420;
    border-bottom: 1px solid #243b31;
}

.code-block-assistant .code-badge-assistant {
    background-color: #064e3b;
    color: #6ee7b7;
    border: 1px solid #059669;
}

.code-block-assistant .code-filename {
    color: #a7f3d0;
    font-weight: 600;
}

/* Style 2: Informative Library Code (Library Interfaces, Internals, Reference SPIs) */
.code-block-library {
    border-color: #3b4252;
    border-left: 4px solid #6366f1;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.12);
}

.code-block-library .code-block-header {
    background-color: #1c1f30;
    border-bottom: 1px solid #2d334d;
}

.code-block-library .code-badge-library {
    background-color: #312e81;
    color: #c7d2fe;
    border: 1px solid #4f46e5;
}

.code-block-library .code-filename {
    color: #e0e7ff;
    font-weight: 600;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 24px 0;
    background-color: var(--bg-card);
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid var(--table-border);
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.03);
}

table th, table td {
    padding: 12px 14px;
    text-align: left;
    border-bottom: 1px solid var(--table-border);
    font-size: 14px;
}

table th {
    background-color: var(--table-header-bg);
    color: var(--primary-dark);
    font-weight: 600;
    border-bottom: 2px solid var(--primary-border);
}

table tbody tr:nth-child(even) {
    background-color: var(--table-alt-row);
}

table tbody tr:hover {
    background-color: var(--primary-light);
}

/* Callout Box / Blockquotes */
blockquote {
    margin: 20px 0;
    padding: 14px 18px;
    background-color: var(--blockquote-bg);
    border-left: 4px solid var(--blockquote-border);
    border-radius: 0 8px 8px 0;
    color: #4a5568;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.03);
}

blockquote p:last-child {
    margin-bottom: 0;
}

/* Callout Card (e.g., Reference Box on Index) */
.callout-card {
    background-color: #fffaf5;
    border: 1px solid var(--primary-border);
    border-left: 4px solid var(--primary-color);
    padding: 16px 20px;
    border-radius: 0 8px 8px 0;
    margin: 20px 0;
}

.callout-card h4 {
    margin-top: 0;
    color: var(--primary-dark);
}

/* Architecture Images */
img {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 24px auto;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.06);
    border: 1px solid var(--border-color);
}

/* Links */
a {
    color: var(--primary-color);
    text-decoration: none;
}

a:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

/* Index Table of Contents List */
.toc-list {
    list-style: none;
    padding: 0;
    margin: 24px 0;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.toc-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 16px 20px;
    transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.toc-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(217, 107, 39, 0.1);
    border-color: var(--primary-border);
}

.toc-card a {
    font-size: 16px;
    font-weight: 600;
    color: var(--primary-dark);
    display: block;
    margin-bottom: 6px;
}

.toc-card em {
    font-style: normal;
    font-weight: 600;
    color: var(--text-color);
}

@media (max-width: 860px) {
    .layout {
        flex-direction: column;
    }
    .sidebar {
        width: 100%;
        height: auto;
        position: relative;
    }
    .content-wrapper {
        padding: 24px 20px;
    }
}

/* Chapter Pagination Navigation Footer */
.chapter-nav {
    display: flex;
    justify-content: space-between;
    align-items: stretch;
    margin-top: 48px;
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
    gap: 16px;
}

.chapter-nav-btn {
    display: inline-flex;
    flex-direction: column;
    padding: 12px 18px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--bg-card);
    text-decoration: none;
    color: var(--text-color);
    transition: all 0.2s ease-in-out;
    min-width: 220px;
    max-width: 48%;
}

.chapter-nav-btn:hover {
    border-color: var(--primary-color);
    background-color: var(--primary-light);
    transform: translateY(-1px);
    box-shadow: 0 4px 10px rgba(217, 107, 39, 0.1);
}

.chapter-nav-btn .nav-direction {
    font-size: 11.5px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.6px;
    color: var(--primary-dark);
    margin-bottom: 4px;
}

.chapter-nav-btn .nav-title {
    font-size: 14px;
    font-weight: 600;
    color: var(--heading-color);
    line-height: 1.35;
}

.chapter-nav-btn.next {
    margin-left: auto;
    text-align: right;
}

@media (max-width: 600px) {
    .chapter-nav {
        flex-direction: column;
    }
    .chapter-nav-btn {
        max-width: 100%;
        width: 100%;
        text-align: left;
    }
    .chapter-nav-btn.next {
        text-align: left;
    }
}